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Intrinsically Safe Listing for Zone 21

Question asked by kgrohs on Apr 30, 2020
Latest reply on May 3, 2020 by chiefns830

I am looking at a portable hand-held instrument for use in a Class I, Div. 2, Group B,C,D (Zone 1) and Class II, Div. 1, Groups F,G (Zone 21) area. The instrument I am looking at has the following listing. I am able to determine that the equipment will work for my Class I area as it is suitable for Class I, Zone 0, by the Intrinsic Safety listing of AEx ia,  gas group IIC, and temperature rating of T4. I am a bit confused about the Class II (zone 21) area, however, and am hoping one or more of you may help.

 

The equipment is listed as IP65 under the IEC Ex system. I am not recognizing something to indicate to me that the instrument holds a listing for the Class II (zone 21) area, however. I don’t see a IIIB for the approval but perhaps the ia makes it allowable for the combustible dusts? Informational note No. 1 of NFPA 70, 506.2 allows for intrinsic safety but does mention ANSI/ISA 61241-11 Electrical Apparatus for Use in Zone 20, Zone 21, and Zone 22 Hazardous (Classified) Locations – Protection by Intrinsic Safety  “iD.” Informational Note No. 2 of the same section states: “Intrinsic safety is designated level of protection “iaD” or “ia” for use in Zone 20 locations. Intrinsic safety is designated level of protection “ibD” or “ib” for use in Zone 21 locations. Intrinsic safety is designated type of protection “ic” for use in Zone 22 locations.”

 

My question is whether the ia in the information below makes this portable instrument acceptable for the Class II (Zone 21) location or if it would only be acceptable if the certification was made by including ANSI/ISA 31241-11 or other acceptable standard for testing? The instruments certification sheet indicates the following requirements and markings.

 

Applicable Requirements

I am excluding the CAN/CSA here.

ANSI/UL 60079-0:09        Electrical Apparatus for Explosive Gas Atmospheres – Part 0: General Requirements

ANSI/UL 60079-11:09      Electrical Apparatus for Explosive Gas Atmospheres – Part 11: Intrinsic Safety “I”

 

Markings

-              Certificate reference (“CSA 10 2283414”);

-              Hazardous Location designation for Canada: “Cl I, Zn 0 Exia IIC T4” or “Cl I, Zn 0 Ex ia IIC 143°C”;

-              Hazardous Location designation for the US: “Cl I, Zn 0 AExia IIC T4” or “Cl I, Zn 0 AEx ia IIC 143°C”;

-              Ambient Temperature (“-10 Deg. C < Ta  < + 40 Deg. C” or “-10 Deg. C < Ta  < + 50 Deg. C”).

-              Um value (“Um = 5.6 V”)

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